Official Circulars and Notices. [may, 



or spanning movement character- The mode of progression is 



istic of this family. continuous. 



Other Saw flies : — ■ 

 The Nematus laricis, or Small Has a black head, and body is 



Larch Sawfly caterpillar has a greyish green. 



•brown head, is grass green or Feeds and grows' till the end 



greenish brown in colour. It is of August, 

 full grown in July. 



The larvae leave the trees when full fed and spin cocoons in which 

 they live till the spring when they pupate. The cocoons may be looked 

 for under the affected tree not only near the trunk but also over the 

 whole surface covered by the crown of the tree. The cocoons are found 

 in the soil under the moss and litter that usually cover the ground 

 under larch trees and this must be turned back when the cocoons are 

 ■being hunted for. These are dark brown and cylindrical with rounded 

 ends, and about half an inch long. 



The adult Sawfly on emerging from the cocoon, after the pupal 

 stage is over, is in general appearance black, with glassy wings. The 

 female flies at once to the lower branches of the tree, to lay her eggs, 

 but apparently much of the life of the insect in this stage is spent on 

 the wing and round the upper branches. It can therefore easily be 

 overlooked and is difficult to identify at any distance. The Large Larch 

 Sawfly is nearly twice as long as the Small Larch Sawfly and can be 

 distinguished from the latter w T hich is quite black by the red segments 

 of the abdomen. 



Larch plantations that are suspected of having been attacked should 

 also be examined with the object of discovering traces of infestation. 

 This work may be carried out from the middle of June to the end of 

 November. The symptoms to be looked for are as follows : In June and 

 July a search should be made on the terminal shoots of the branches 

 for signs of eggs, which are laid alternately in two rows. The number 

 is usually about twenty, but as many as forty have been found. The 

 easiest sign, however, to notice, is the distortion of the current year's 

 shoots, which often curl up when eggs have been laid in them. A 

 closer examination will generally reveal the incisions made by the 

 Sawfly 's ovipositor on the concave side of the curled shoot. The slits 

 where the eggs have been laid resemble small eyes less than one-tenth 

 inch in diameter. A little later, in July and August, the needles should 

 be examined for signs of feeding. The young caterpillars do not eat 

 the whole needle but bite pieces out of the edges of it. At a later date 

 when the caterpillars are more fully grown, and separate in search of 

 food the whole rosette of needles will be. eaten or only a stump left. 

 In August and September these defoliated dwarf shoots may sprout 

 again, and present almost the same appearance as they did in May, 

 •except of course that the growth is irregular. These indications are 

 to be found in varying intensity on all trees that have been attacked, 

 but in the case of a serious infestation the trees present a brown and 

 withered appearance which is noticeable hundreds of yards away, and 

 after a little practice the more seriously affected trees can be picked 

 out at a distance. When the attack is very serious and prolonged the 

 trees die and there is then no difficulty in realising the damage done. 



